A former FBI counter-terrorism agent says lawmakers could make mass murders less likely. "What we need to do is keep the ownership of guns known to the government, so we know who has what,” said security consultant Gamal Abdel-Hafiz. “And I know a lot of people are against that.”

A woman is seen with what appears to be blood on her shirt and skirt after a shooting at Pulse, a gay nightclub in Orlando, on June 12, 2016. (Photo: Univision Florida Central via EPA) (Photo: UNIVISION FLORIDA CENTRAL / HAN)

22 years of investigating terrorism built up some frustration for Abdel-Hafiz. The Orlando massacre adds to it.

"He shouldn't have been able to buy a gun legally. He shouldn't,” said Abdel-Hafiz about 29 year-old Omar Mateen. He says 3 FBI interviews should have been enough to keep Mateen on the radar, but he also knows why he wasn't. "Once you investigate someone and clear them, you have to remove them from the watch list by law,” he explained Monday from his office in Dallas.

And even if Mateen had been on a terror watch list, or no-fly list, that would not have prohibited him from legally buying weapons, including a high velocity semi-automatic assault rifle.

Former FBI counter-terrorism agent Gamal Abdel-Hafiz says lawmakers could make mass murders less likely. "What we need to do is keep the ownership of guns known to the government, so we know who has what,”

"That means the list is useless then,” the former agent said. Efforts to ban weapon sales to those on watch lists have been blocked in Congress. Some lawmakers say the lists could violate a person's second amendment rights. "As long as our politicians keep fighting each other for the sake of fighting each other, more innocent people will keep on dying,” he said.

Gamal Abdel-Hafiz is now consulting on a government counter violent extremist project to reduce the threat of homegrown terrorists. He’s an avid gun owner. But he says the carnage in Orlando shows that gun law must be part of the conversation.